The ring crush test (RCT) explained

The ring crush test (RCT) is used to determine the ring crush resistance of a paper strip formed into a ring with a standardized length and width. This test is performed to ISO 12192 and TAPPI T 822.

The ring crush test is similar to the short-span compression test in that the strength of the liner or fluting is measured both in the machine direction and perpendicular to it. It is important that force application to the specimen is exactly perpendicular during these tests.

The results of this test are highly dependent on proper specimen preparation. Specimen and guides must be exactly parallel to ensure accurate determination of ring crush strength. As the ring crush test provides information about specimen buckling behavior rather than crush behavior, it is increasingly being replaced by the short-span compression test.